Hardware is measured three ways — fractions on American parts, decimals on calipers, millimeters on metric equipment — and every sizing mistake starts with a bad conversion. Use the calculator above (or this chart) to translate between all three instantly.
Common Hardware Sizes: Fraction → Decimal → MM
| Fraction | Decimal (in) | MM |
|---|---|---|
| 1/16" | 0.0625 | 1.59 |
| 1/8" | 0.125 | 3.18 |
| 3/16" | 0.1875 | 4.76 |
| 1/4" | 0.25 | 6.35 |
| 5/16" | 0.3125 | 7.94 |
| 3/8" | 0.375 | 9.53 |
| 7/16" | 0.4375 | 11.11 |
| 1/2" | 0.5 | 12.7 |
| 9/16" | 0.5625 | 14.29 |
| 5/8" | 0.625 | 15.88 |
| 3/4" | 0.75 | 19.05 |
| 7/8" | 0.875 | 22.23 |
| 1" | 1.0 | 25.4 |
| 1-1/4" | 1.25 | 31.75 |
| 1-1/2" | 1.5 | 38.1 |
| 2" | 2.0 | 50.8 |
Measuring a metric part for an inch-sized replacement? Convert to decimal inches, then pick the nearest standard fraction — rubber's flexibility forgives a 64th. Find your part: grommet size chart, washer finder, mount chart, or all guides & tools.